Multi-test gravelometer

ABSTRACT

A gravelometer ( 20 ) includes a base unit ( 30 ) comprising compressed air receiver tank ( 40 ) having wheels ( 42 ) and feet ( 44 ). Main frame ( 46 ) connects tank ( 40 ) to a media gun frame or mount ( 50 ) and includes a bore ( 52 ) for releasably receiving and supporting a media gun ( 54 ) having a mounting flange ( 70 ) so that media inlet ( 56 ) is upwardly oriented and gun barrel or media outlet ( 57 ) extends through gun mount ( 50 ). Media inlet ( 56 ) interconnects via elongated con-duit ( 58 ) to a media supply system ( 60 ) which includes media supply hopper ( 62 ) and vibratory feeder assembly ( 64 ). A control system ( 80 ) having operator control panel ( 82 ) controls operations. A modular target box or chamber ( 90 ) is aided in being releasably connected to base unit ( 30 ) by locator pins ( 102 ). Chamber ( 90 ) includes media inlet ( 92 ), media outlet ( 94 ), which connects to spent media reclaim chamber ( 100 ), and specimen window ( 96 ) having a target holding toggle clamp ( 98 ).

This application claims priority from and benefit of the filing date ofU.S. provisional application Ser. No. 60/072,840 filed Jan. 28, 1998.

BACKGROUND OF THE INVENTION

The present invention relates generally to an apparatus for testing thechipping resistance and adherence of surface coatings. Moreparticularly, the invention relates to a gravelometer havingmulti-standard capabilities so that a user need not purchase a pluralitygravelometers each dedicated to a particular testing standard. Inaccordance with the present invention, a gravelometer base unitselectively receives one of a plurality of target chambers to enclosethe sample being tested, and one of a plurality of media guns forpropelling the media at the test sample secured in the target chamber.The particular target chamber and media gun utilized depend upon theparticular testing standard to be followed.

Gravelometers and their use for testing the adhesion and chip resistanceof coatings to a test panel or other specimen are generally well known.Typically, the gravelometer is adapted to project a specified volume ofstandardized blasting media, such as gravel, split shot, buck shot,sand, or the like, at a test panel or other object coated with the paintor other coating being tested. The test panel is housed in or otherwisesurrounded by a “target chamber” so that the media is contained forsafety. The media is typically propelled toward the test specimen from amedia “gun” under the Force of compressed air at a specified pressureand flow rate. Media is fed into the media gun in a controlled mannereither manually or through use of an automatic feeding apparatus. Oncethe supply of media is exhausted, the test panel is removed from thetarget chamber, examined, and evaluated in accordance with particularchipping and adherence standards.

In the United States of America, gravelometers, their use, and testspecimen evaluation, are generally carried out in accordance withRecommended Practice SAE J400 of the Society of Automotive Engineers(SAE J400). In general, SAE J400 specifies test equipment, testconditions, test procedures, and test specimen evaluation. Moreparticularly, SAE J400 specifies the use of a particular media(standardized gravel), a particular compressed air gun for projectingthe gravel, a particular distance between the test specimen and the gun,particular angular orientations of the test specimen relative to theprojection path of the media, and other testing parameters. As such,heretofore, those desiring to test coatings in accordance with SAE J400were required to purchase a dedicated SAE J400 compliant gravelometernot usable to conduct testing in accordance with any other standard.

Likewise, those desirous of testing a specimen in accordance with acommon European standard established by Verband der Automobilindustrie(VDA), had to purchase a dedicated VDA compliant gravelometer. The SAEJ400 and VDA standards use different media and different types of mediaguns. Therefore, neither a dedicated SAE J400 gravelometer nor adedicated VDA gravelometer is usable to conduct coating tests under adifferent standard.

In addition to being generally inconvenient, the need to purchase,operate, and maintain multiple prior gravelometers was found to be quiteexpensive and generally undesirable. Also, the multiple gravelometersconsume large amounts of valuable shop floor space.

Another problem associated with prior gravelometers is their inabilityto receive and contain large three-dimensional test specimens. Forexample, with coatings, it is often desirable to test the chippingresistance after the coating has been applied to an actual end productsuch as a wheel, a spring, or an automobile body part. With priorgravelometers, their is no convenient and effective way of subjectingsuch three-dimensional objects to a test without departing from the testprocedures or without purchasing yet another specialized gravelometermade for such parts.

SUMMARY OF THE INVENTION

The present invention therefore relates to a gravelometer which is ableto belconfigured with any one of a plurality of target chambers andmedia guns to comply with SAE J400, VDA, or any other testing standard.

In accordance with a first aspect of the invention, a gravelometerapparatus includes a media gun mount extending from a frame member. Thegun mount includes a bore adapted to receive a barrel of an associatedmedia gun and a media gun fastening device for fixedly and releasablysecuring the media gun relative to the mount so that the gun barrel isplaced in the bore. A first enclosed target chamber is releasablysecured to the frame member in an operative position so that the barrelof an associated media gun secured to the frame member is directed intoan enclosed interior space of the target chamber through an inlet. Thetarget chamber includes a target support for fixedly retaining a targetspecimen in an operative position so that testing media projectedoutwardly from an outlet in the barrel of the associated gun impingesupon the target specimen and is retained in the enclosed interior space.A media supply system is connected to the frame member and included amedia hopper and a media feeder for conveying media from the hopper to amedia inlet of the associated media gun.

In accordance with another aspect of the present invention, a multi-testgravelometer for performing coating testing operations based on at leasttwo different standards includes a frame adapted for releasablyreceiving and retaining an associated one of at least first and secondmedia guns in an operative position so that a media inlet of the gun ispositioned to receive testing media and a media outlet of the gun ispositioned to project testing media toward a testing target. Acompressed air supply is adapted for communication with an air inlet ofthe gun. The gravelometer includes means for selectively and releasablyconnecting one of a plurality of different two-dimensional specimentarget chambers to the frame by in an operative position so that themedia outlet of the gun is directed into and enclosed by an interiorportion of the target chamber in line with a target specimen supportregion thereof.

In accordance with still another aspect of the present invention, amodular gravelometer apparatus includes a base unit having a frame. Acompressed air tank is secured to the frame. A plurality of differentmedia guns, each conformed in accordance with a particular testingstandard, are adapted for individual and selective operative securementto the base unit frame by at least one releasable connector. Each of themedia guns includes a media inlet adapted to receive testing media, amedia outlet for projecting the testing media outwardly along a targetpath, and a compressed air inlet adapted for selective fluidcommunication with the compressed air tank. A plurality of differenttwo-dimensional specimen target chambers are each conformed inaccordance with one of the testing standards and adapted for individualand selective securement to the base unit in an operative position usingat least one releasable connector. Each target chamber defines anenclosure, a media inlet to the enclosure, and an air exhaust vent, andeach chamber includes a target specimen securement device forselectively and releasably securing a target specimen in an operativeposition in line with the target path so that testing media projectedfrom an operatively secured media gun impinges on the operativelysecured target specimen.

In accordance with yet another aspect of the present invention, a methodof constructing a gravelometer apparatus to perform testing inaccordance with one of at least two different testing standards includesselecting one of a plurality of different media projecting guns. Each ofthe guns is conformed in accordance with a different testing standard.The selected gun is operatively and releasably secured to a framemember. One of a plurality of different target chambers is selected tocorrespond with the selected one: of the media guns. Each chamber isconformed in accordance with one of the different testing standards. Theselected chamber is operatively and releasably securing to the framemember so that a testing media outlet of the operatively secured mediagun is directed into an enclosed interior portion of the operativelysecured target chamber. An air inlet of the operatively secured mediagun is connected to a supply of compressed air.

One advantage of the present invention is that it eliminates the needfor multiple gravelometers each dedicated to a particular testingstandard.

Another advantage of the present invention is that it provides agravelometer base unit to which any one of a plurality of media guns andmany one of a plurality of target chambers are easily and convenientlyconnected to construct a gravelometer in accordance with any testingstandard.

Still another advantage of the present invention is that athree-dimensional specimen target chamber is easily and selectivelyconnectable to any of the target chambers as needed for testingthree-dimensional specimens in accordance with any testing standard.

Yet another advantage of the present invention is that a wide variety ofblast media such as gravel, split shot, buckshot, sand, or MDOT 25A, isable to be used for testing procedures.

A further advantage of the present invention is that it is more easilyand less expensively repaired or calibrated.

Still other benefits and advantages of the invention will become readilyapparent to those skilled in the art upon reading and understanding thefollowing detailed specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangementsof parts, and be carried out in certain steps and arrangements of steps,preferred embodiments of which will be described in detail in thisspecification and illustrated in the accompanying drawings which form apart hereof and wherein:

FIG. 1 is a front elevational view of a gravelometer in accordance withthe present invention;

FIG. 2 is a top plan view of the gravelometer shown in FIG. 1;

FIGS. 3 and 4 are right and left side elevational views of thegravelometer shown in FIG. 1, respectively;

FIG. 5 is an exploded front elevational view of a modular SAE J400 mediagun in accordance with the present invention;

FIG. 6 is a top plan view of the SAE J400 gun shown in FIG. 5, with thegun fully assembled;

FIG. 7 is a right side elevational view of the SAE J400 media gun shownin FIG. 6;

FIG. 8 is a front elevational view diagrammatically illustrating amodular VDA media gun and its connection with a media supply system inaccordance with the present invention;

FIGS. 9A-9D are rear elevational, left side elevational, frontelevational, and top plan views, respectively, of a modular SAE J400 90°target chamber in accordance with the present invention (with FIGS. 9Cand 9D partially broken away);

FIGS. 10A-10D are rear elevational, left side elevational, frontelevational, and top plan views, respectively, of a modular VDA 90°target chamber in accordance with the present invention (with FIGS. 10Cand 10D partially broken away);

FIGS. 11A-11D are rear elevational, left side elevational, frontelevationlal, and top plan views, respectively, of a modular SAE J40045° target chamber in accordance with the present invention;

FIGS. 12A-12D are rear elevational, left side elevational, frontelevational, and top plan views, respectively, of a modular VDA 45°target chamber in accordance with the present invention;

FIG. 13A illustrates a three-dimensional specimen target chamber as itis releasably connected to a two-dimensional specimen modular targetchamber for purposes of testing three-dimensional specimens;

FIG. 13B is a left side elevational view of the three-dimensionalspecimen target chamber shown in FIG. 13A; and,

FIG. 13C is a top plan view of the three-dimensional specimen targetchamber releasably connected to a two-dimensional specimen targetchamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to!FIGURES 1-4, a gravelometer in accordance with thepresent invention is illustrated generally at 20. The gravelometerincludes a base unit 30 to which modular components are selectivelyconnected as is described in detail below. The base unit 30 comprises asource of compressed air (or other gas) which may be a receiver tank 40connected to al shop air supply or another source. The tank 40 issupported above a shop floor by a combination of wheels 42 and feet 44that facilitate movement of the gravelometer 20 as desired.

The base unit 30 also includes a main frame 46 connected to the upperregion of the tank 40. A media gun frame or mount 50 is connected to themain frame (or formed as a one-piece construction therewith) andincludes a bore 52 or other means for releasably receiving a media gun54 and operatively supporting the gun so that a media inlet 56 of thegun is upwardly oriented and so that the gun barrel (media outlet) 57extends through the gun mount 50.

As shown herein, the media inlet 56 of the gun 54 is connected to anelongated conduit 58. An open upper end of the conduit 58 is incommunication with an automatic media supply system 60. The media supplysystem 60 receives and retains a supply of gravel or other blast mediain a hopper 62 and includes means for dispensing the media from thehopper into the, gun inlet conduit 58 in a controlled manner. As shownherein, the dispensing means comprises a vibratory feeder assembly 64supported by the frame 50, although any other suitable feeding means maybe employed. Alternatively, an operator of the apparatus 20 is able tomanually control the flow of media into the gun inlet 56.

FIGS. 2-4 illustrate the preferred means for selectively, operatively,and releasably securing a modular media gun 54 to the gun frame 50 inaccordance with the present invention. A modular SAE J400 compliantmedia gun 54 in accordance with the present invention includes aradially enlarged mounting flange 70 (see also FIGS. 5-7) that liesadjacent to a face of the frame 50 when the gun is operatively supportedby the frame as described. The apparatus 20 includes means forreleasably engaging the gun 54 and securing the gun in the operativeposition without requiring use of wrenches, screwdrivers, or liketools—i.e., through use of manually operable connectors. For example, asshown herein, first and second toggle clamps 72,74 (FIG. 2) are providedto selectively and releasably engage the radially enlarged mountingflange 70 of the gun and prevent any movement of the gun 54 relative tothe gun frame 50. Alternatively, the gun may be operatively secured tothe frame 50 via means such as a collar assembly, a threaded or key-likeconnection, bolts, pins, or other fasteners, or any other suitable meansthat allows the gun 54 to be quickly and easily affixed to and separatedfrom the frame 50. Mating locator pins/apertures or the like arepreferably provided on the gun/frame to ensure proper installation andalignment of the gun 54.

As is shown in FIGS. 5 and 6, the modular SAE J400 gun comprises an airnozzle 76 which threadably or otherwise mates in a fluid-tight mannerwith a compressed air inlet 78. The nozzle 76 is connected to thecompressed air supply 40 using suitable conduit and one or more valvesthat allow the selective flow of compressed air to the gun nozzle 76.

FIG. 8 diagrammatically illustrates an alternative media gun 54′ thatcomplies with VDA testing standards rather than SAE standards. Likecomponents relative to the SAE J400 gun 54 are indicated using likereference numerals with a primed (′) suffix. Other than having aslightly different configuration and different dimensions, the guns54,54′ are similar in all respects. Also, the gun 54′ is preferably usedto propel chill-cast iron abrasive. Thus, those skilled in the art willrecognize that either gun 54,54′, or a gun manufactured in accordancewith another standard and the present invention, is selectively,operatively, and releasably connectable to the gun support frame 50 ofthe gravelometer base unit 30 as described above and required by aparticular testing standard in an easy and convenient manner without useof tools.

With reference again to FIGS. 1 and 2, a control system 80 is connectedto the main frame 46 and controls all machine operations. The controlsystem includes an operator control panel 82 having a plurality ofoperator input/output devices 84 thereon. The control system 80 controlsthe operation of the media supply system 60 and the flow of compressedair (or other gas) from the supply tank 40 to the nozzle 76,76′ of amedia gun 54,54′ through any suitable conventional hose(s).

In FIGS. 1-4 it is shown that a modular target box or chamber 90 is alsoselectively, operatively, and releasably connected to the base unit 30of the gravelometer apparatus 20 by any suitable means such as clips C1,interlocking parts, bolts, pins, or any other fasteners. The targetchamber 90 defines an enclosure which shields a test specimen andprevents the escape of the blasting media after it impacts a testspecimen. The target chamber 90 includes a media inlet 92, a mediaoutlet 94, and a specimen window 96. When the target chamber isoperatively and releasably connected to the base unit 30 as shown, themedia inlet 92 seals against the frame 50 to prevent the escape of mediaand to allow the projection of the media from a gun barrel 57,57′ intothe chamber 90 along a horizontal projection or target path. Thespecimen window 96 is aligned with the gun barrel 57,57′, and a toggleclamp 98, or other means such as a frame, releasably and firmly securesa flat, two-dimensional test panel or other specimen in the window 96 sothat the window is sealed by the specimen and any associated specimensupport structure. In this manner, media propelled into the targetchamber 90 along the horizontal projection path impinges upon the testsample but is contained within the target chamber. As is described infull detail below, the angular orientation of the test specimen and itsdistance from the gun barrel 57,57′ depends on the particular gun/targetchamber combination connected to the base unit 30. As shown herein, thechamber 90 is an SAE J400 compliant target chamber which secures thespecimen at a 90° angle relative to the horizontal media projectionpath. The spent media falls through the media outlet 94 into a mediareclaim chamber 100.

As noted, the subject multi-test gravelometer 20 comprises means forselectively, operatively, and releasably connecting the modular targetchamber 90 to the base unit 30 so that any one of a plurality ofdifferent modular target chambers may be connected to the base unit asdesired to comply with a particular testing standard in an easy andconvenient manner without aid of tools. As shown herein, a plurality ofclips, clamps, or like connectors C1 (FIGS. 2-4) are utilized. Also, forpurposes of facilitating releasable connection of a target chamber 90,it is preferred that the frame 50 include one or more locator pins 102(FIGS. 1 and 4) that each engage a mating aperture 103 (FIG. 9D) of thetarget chamber 90 to facilitate the proper interconnection of thechamber 90 and the frame 50. A target chamber safety switch is connectedto the control system 80 and senses the proper connection of the targetchamber 90 to the frame 50. In the event the chamber 90 is not properlyconnected to the frame, the control system will not allow operation ofthe apparatus 20. Of course, the chamber 90 can be releasably connectedto the frame 50 through use of any suitable manually operable“quick-disconnect” type retainers.

FIGS. 9A-9D illustrate the SAE J400 90° target chamber 90 in fulldetail. FIGS. 10A-10D, 11A-11D, and 12A-12D illustrate alternativemodular target chambers 190, 290, and 390, respectively, in accordancewith the present invention for selective and releasable interconnectionto the gravelometer base unit 30 in the same manner as the chamber 90 tocomply with al variety of other testing standards as desired. The partsof the modular chambers 190,290,390 relative to the modular chamber 90are indicated with like reference numerals that are 100, 200, and 300units greater, respectively, than corresponding parts of the targetchamber 90. The modular target chambers 90,190 secure a test specimen ata 90° angle relative to the media projection path while the targetchambers 290,390 secure a test specimen at a 45° angle relative to theprojection path.

Each modular target chamber 90,190,290,390 also includes a vent opening104 formed therethrough for the exhaustion of the compressed lair thatpropels the blast media. A dust filter 108 (FIG. 9A) is secured in thevent opening 104 of each tar get chamber and blocks the passage ofairborne particulates through vent opening 104. As shown herein, thefilter 108 is secured in the opening 104 through use of a frame 106which slidably receives the filter. Other filter securement means may beused as desired.

FIGS. 13A-13C depict a modular three-dimensional specimen target chamber490 in accordance with the present invention. The three-dimensionalspecimen target chamber 490 is selectively and releasably clamped orotherwise fastened to one of the modular 90° target chambers 90,190 andincludes a media inlet 492 which communicates with the target chamberspecimen window 96,196. Rather than securing a two-dimensional panel orother specimen in the window 96,196, the window is left open and athree-dimensional specimen, such as a spring, wheel cover, or the like,is positioned in the three-dimensional specimen target chamber 490. Thespecimen is placed in the chamber 490 through a hinged access door 494.The chamber 490 preferably also includes an adjustable clamping bar 496movable toward and away from the window 492 or other like means forfixedly securing a specimen is a desired location in line with thewindow 492. The media propelled by a gun 54,54′ passes through thechamber 90,190 and into the three-dimensional target chamber to impingeon the three-dimensional specimen housed therein. The modularthree-dimensional specimen chamber 490 is selectively and releasablyconnected to one of the 90° two-dimensional specimen chambers 90,190using manually operable retainers such as clips C2 that selectivelyengage studs 498, or through use of interlocking parts of the chambers90,490, bolts, pins, clamps, or any other suitable connectors.

The invention has been described with reference to preferredembodiments. Obviously, modifications and alterations will occur to tohers upon a reading and understanding of the preceding specification. Itis intended that the invention be construed as including all suchmodifications and alterations insofar as they fall within the scope ofthe appended claims and equivalents thereof.

Having thus described the preferred embodiments, the invention isclaimed to be:
 1. A multi-test gravelometer for performing coatingtesting operations in accordance with at least two different standardsas desired by a user, said gravelometer comprising: first and secondmedia guns constructed according to respective first and seconddifferent testing standards; a frame including a mount for individuallyreleasably receiving and retaining said first and second media guns inan operative position wherein a media inlet of said releasably retainedgun is positioned to receive testing media and a media outlet of saidreleasably retained gun is positioned to project testing media toward atesting target on a target path; a compressed air supply adapted forcommunication with an air inlet of said releasably retained gun; atleast two different target chambers for supporting a test specimen in arequired orientation for impingement by media traveling on said targetpath, said at least two different target chambers respectivelyconstructed according to at least two different testing standardsincluding said first and second testing standards, said at least twodifferent target chambers adapted for being individually releasably andoperatively connected to said frame to receive media traveling on saidtarget path.
 2. The multi-test gravelometer as set forth in claim 1further comprising: a media supply system connected to said frame, saidmedia supply system including a media hopper for containing a supply oftesting media and a media feeder for communicating testing media fromthe hopper to the medial inlet of the associated media gun secured tosaid frame.
 3. The multi-test gravelometer as set forth in claim 2wherein said media feeder comprises a vibratory feeder.
 4. Themulti-test gravelometer as set forth in claim 1 further comprising: atleast one clamp connected to said frame and adapted for selectivelyengaging a radially enlarged flange portion of said associated mediagun, said at least one clamp, when closed, fixedly securing said flangein abutment with said frame.
 5. The multi-test gravelometer as set forthin claim 1 further comprising: a plurality of locator pins extendingfrom said frame for engagement with mating apertures of each of said atleast two target chambers; and, a plurality of retaining clips forselectively and releasably interconnecting each of said at least twotarget chambers to said frame.
 6. The multi-test gravelometer as setforth in claim 1, wherein said at least two target chambers comprise: atwo-dimensional specimen target chamber selectively, operatively, andreleasably secured to said frame; and, a three-dimensional specimentarget chamber selectively, operatively, and releasably connected tosaid two-dimensional specimen target chamber, said three-dimensionalspecimen chamber adapted to receive and support a three-dimensionaltarget specimen for impingement by media traveling on said target path.7. A multi-test gravelometer for performing coating testing operationsin accordance with at least two different standards as desired by auser, said gravelometer comprising: a frame adapted to receive andselectively releasably retain, individually, both an SAE compliant mediagun and a VDA compliant media gun in an operative position wherein amedia inlet of said selectively received and retained gun is positionedto receive testing media and a media outlet of said associated gun ispositioned to project testing media toward a testing target; acompressed air supply adapted for communication with an air inlet ofsaid associated gun; and, means for releasably securing any one of aplurality of different two-dimensional specimen target chambers to saidframe in an operative position so that the media outlet of an associatedgun is directed into and enclosed by an interior portion of anoperatively secured target chamber in line with a target specimensupport region thereof.
 8. A method of constructing a gravelometerapparatus to perform testing in accordance with either of at least twodifferent testing standards, as desired, said method comprising:selecting a first media projecting gun to perform testing in accordancewith a first testing standard; selecting a second media gun to performtesting in accordance with a second testing standard, said first andsecond guns conformed differently in accordance with said first andsecond testing standards; operatively and releasably securing said firstmedia gun to a frame member and to a source of compressed air to performtesting in accordance with said first testing standard or operativelyand releasably securing said second media gun to said frame member andto said source of compressed air to perform testing in accordance withsaid second testing standard; selecting one of a plurality of differenttarget chambers based upon which of said first and second media guns isoperatively and releasably secured to said frame member; and,operatively and releasably securing said selected one of said targetchambers to said frame member.
 9. A method of testing a coating on atarget specimen according to at least two different standards, saidmethod comprising: (a) selecting one of a plurality of testing standardsfor testing coating properties; (b) selecting testing media inaccordance with said selected testing standard; (c) selecting one of aplurality of different media projecting guns so that said selected guncomplies with said selected testing standard; (d) operatively andreleasably securing said selected media gun to a frame member; (e)selecting one of a plurality of different target chambers whichcorresponds to said selected media gun and said selected testingstandard; (f) operatively and releasably securing said selected targetchamber to said frame member so that a testing media outlet of saidoperatively secured media gun is directed into an interior portionthereof along a target path; (g) connecting a fluid inlet of saidoperatively secured media gun to a supply of compressed fluid; (h)selecting a target specimen and operatively securing said targetspecimen to said selected target chamber in line with said target path;(i) selectively feeding said selected testing media to a media inlet ofsaid operatively secured media gun and selectively communicatingcompressed fluid from said supply to said fluid inlet of saidoperatively secured media gun so that said operatively secured media gunprojects said selected testing media outwardly from its outlet alongsaid target path for impingement on said operatively secured targetspecimen; and, (j) repeating steps (b)-(i) for at least two differenttesting standards selected from said plurality of testing standards instep (a).
 10. A multi-test gravelometer apparatus comprising: a framecomprising a mount; first and second different media guns for propellingtest media under force of compressed air on a target path, said firstand second media guns constructed according to first-and seconddifferent testing standards, respectively, said first and seconddifferent media guns selectively individually operatively connected tosaid frame by said mount and each comprising; (i) a media inlet; (ii) amedia outlet; and, (iii) a compressed air inlet; and, first and seconddifferent specimen target chambers constructed according to said firstand second different standards, respectively, said first and secondtarget chambers selectively individually and operably connected to saidframe in an operative position, each of said first and second targetchambers including a specimen support in line with said target path,said specimen support adapted to support a target specimen forimpingement by media traveling on said target path.